What to Expect During Defecography

A defecography is a test in which a continual series of X-rays are taken during a bowel movement to identify any structural or functional problems in the anus, rectum or pelvic floor.

To get a clear representation of a bowel movement, a thick barium paste will be inserted into the rectum of the man or woman with a device similar to a caulking gun. The barium ensures high contrast on the X-ray images as the paste is gradually expelled from the bowel.

Defecography can also be performed using a magnetic resonance imaging (MRI) machine instead of an X-ray to avoid radiation. When the procedure involves the use of real-time X-ray video, it is often referred to as cinedefecography.

Indications for Use

While defecography has fallen out of favor in recent years due to inadequate training in the technique, it offers doctors a more dynamic evaluation of the variety of problems affecting the anus and rectum.

Among them:

Anal pain
Chronic constipation
Fecal incontinence (inability to control bowel movements)
Incomplete evacuation (inability to clear the bowels entirely)
Rectal prolapse (where the rectum slips outside of the anus)
Cystocele (bulging of the bladder into the vagina)
Enterocele (bulging of the small bowel into the vagina and rectum)
Rectocele (bulging of the wall of the rectum into the vagina)
Dyssynergic defecation (where certain nerves and muscles of the pelvic floor fail to work during a bowel movement)

What to Expect

Unlike a colonoscopy, you may not need to undergo a complete clean-out preparation. Some centers may simply ask you to use an enema before your appointment. You would then need to refrain from eating for at least two hours prior to the exam.

To perform the procedure, barium paste would be slowly injected into the rectum until full.

Filling it to capacity stimulates the nerves to empty the bowel as it does under normal conditions.

You would then be asked to sit on a special toilet to evacuate the paste. You would be instructed to squeeze and strain as you expel the paste entirely or as much as you can, As this is happening, either a series of X-ray or an X-ray video will be taken.

The procedure takes approximately 15 to 30 minutes in total. While the exam may seem awkward and uncomfortable, it typically doesn't cause any pain.

In some cases, the doctor may request that you drink a barium solution an hour before the exam so that images of your small intestine can also be taken. In women, a small amount of barium paste may be smeared on the vagina to get a better image of the space between the vaginal wall and rectum.

A Word From Verywell

The value of a defecographic exam is largely limited by the expertise and experience of the radiological staff. To this end, it is important that the procedure is overseen and the results interpreted by a specialist experienced in anorectal motility.

_Sources:

Kim, A. "How to Interpret a Functional or Motility Test - Defecography." J Neurogastroenterol Motility. 2011; 17:416-20. DOI: 10.5056/jnm.2011.17.4.416.

Olson, C. "Diagnostic Testing for Fecal Incontinence." Clinic Colon Rectal Surg. 2014; 27:85-90. DOI: 10.1055/s-0034-1383901.